The invention relates to a manufacturing method of a semiconductor device and particularly, to a technique effectively applied to a manufacturing method of a semiconductor device using, for example, a silicon carbide substrate.
Japanese Unexamined Patent Application Publication No. 2006-108243 describes a technique such as forming an oxide film on the surface of a trench-formed silicon substrate through ozonation and then, annealing the above in an atmosphere including hydrogen.
Japanese Unexamined Patent Application Publication No. 5509520 describes a technique for rounding the corner of a trench to avoid an electric field from concentrating on the corner of the trench. Specifically, as the technique for rounding the corner of a trench, argon (Ar) or silane (SiH4)/argon (Ar) is used for annealing.